The advent of cellular telephone heralds a new phase of two-way portable communication. However, while cellular telephone provides portable two-way communication, it brings a high economic cost for the convenience of being accessible in most geographic locations. To reduce the cost of communication, a cellular telephone is combined with a selective call receiver (pager). The combination cellular telephone and the selective call receiver have separate receiving circuits so both devices may operate, i.e., receive messages independent of each other or even simultaneously. Unfortunately, conventional cellular telephone has a limited power supply and under normal operating conditions is unable to provide a "talk-time" long enough for most users. The limited power supply of the battery is exacerbated when the cellular telephone is combined with other receiving devices because both devices place a higher demand for power on the battery which already has an inadequately short "talk-time."
Therefore, what is needed is a cost effective method and an apparatus to ensure that the battery of the combined cellular telephone and another receiving device can be recharged without missing important calls during charging.